topic Re: Yet another awk question... in Operating System - HP-UX

Yet another awk question...

Jamie Collins — Fri, 15 Oct 2004 15:42:44 GMT

Given:

cat file.txt
Start
id fname lname
-- ----- -----
1 John Wayne
2 Bill Smith
Stop
Start
id fname lname
-- ----- -----
Stop
Start
id fname lname
-- ----- -----
1 Mark Williams
Stop

cat file.awk
awk '/Start/{x=1;y=0}/Stop/{if (y>3){l[y]="\n"; while(i++
Outputs:

id fname lname
-- ----- -----
1 John Wayne
2 Bill Smith

id fname lname
-- ----- -----
1 Mark Williams

How do I print a line before the header...

eg:

This report was run on Sat. May 1, 2005
id fname lname
-- ----- -----
1 John Wayne
2 Bill Smith

This report was run on Sat. May 1, 2005
id fname lname
-- ----- -----
1 Mark Williams

Thanks

Re: Yet another awk question...

Rodney Hills — Fri, 15 Oct 2004 15:45:35 GMT

Use the "BEGIN" clause within awk.

awk 'BEGIN{print "today is something"};/Start/{x=1;y=0}/Stop/{if (y>3){l[y]="\n"; while(i++
HTH

-- Rod Hills

Re: Yet another awk question...

Jamie Collins — Fri, 15 Oct 2004 15:53:33 GMT

That produces the following:

today is something
id fname lname
-- ----- -----
1 John Wayne
2 Bill Smith

id fname lname
-- ----- -----
1 Mark Williams

Is there a way to get it to print the header every time it sees Start??

Re: Yet another awk question...

Rodney Hills — Fri, 15 Oct 2004 15:55:06 GMT

Whoops, I didn't notice you had it before everyline that starts with "id".

Just add an "if" statement-

awk '/Start/{x=1;y=0}/Stop/{if (y>3){l[y]="\n"; while(i++
-- Rod Hills

Re: Yet another awk question...

Jamie Collins — Fri, 15 Oct 2004 16:00:03 GMT

/Start/{x=1;y=0}/Stop/{if (y>3){l[y]="\n"; while(i++}

produces:

This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
Start fname lname
Start ----- -----
Start John Wayne
Start Bill Smith

This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
Start fname lname
Start ----- -----
Start Mark Williams

This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005

Re: Yet another awk question...

Rodney Hills — Fri, 15 Oct 2004 16:02:11 GMT

Whoops again.

If you want it printed when "Start" is found, why not add it their.

awk '/Start/{x=1;y=0; print "This report was run on Sat May 1,2005"}/Stop/{if (y>3){l[y]="\n"; while(i++
-- Rod Hills

Re: Yet another awk question...

Jamie Collins — Fri, 15 Oct 2004 16:06:47 GMT

That works good except when I encounter the blank line:

id fname lname
-- ----- -----

It still prints the header line...

This report was run on Sat May 1, 2005
id fname lname
-- ----- -----
1 John Wayne
2 Bill Smith

This report was run on Sat May 1, 2005
This report was run on Sat May 1, 2005
id fname lname
-- ----- -----
1 Mark Williams

Maybe a nested if would work?

Re: Yet another awk question...

Hein van den Heuvel — Fri, 15 Oct 2004 21:51:08 GMT

awk '/Start/{x=1;y=0}/Stop/{if (y>3){l[y]="\n"; print "hello"; while(i++
Ah, a continuation of an earlier threat.
That solution came form me.
When it sees 'start', it merely starts counting and remembering
When it sees 'stop' AND has seen enough lines it starts to dump its memory with a while loop.

So, for this new requirement you need to add a print in the 'stop' section, just before executing the while... print.
As per above.

In more readable form:

awk '
/Start/{x=1;y=0}
/Stop/ {if (y>3) {
l[y]="\n";
print "hello";
while(i++ }
x=i=0
}
{l[y]=$0;
y+=x}
'

As an alternative you can also overwrite the 'start' line with the desired header, and have the while loop print it out eventually by tweaking its start and end:

awk '/Start/{x=1;y=0;$0="hello"}/Stop/{if (y>3){l[y]="\n"; while(i<=y){print l[i++]}};x=i=0}{l[y]=$0;y+=x}'

Cheers,
Hein

Re: Yet another awk question...

Tim D Fulford — Sat, 16 Oct 2004 04:48:50 GMT

awk 'BEGIN{ print "what ever you want"}; ....'

or pribably a better solution is

perl -ane 'INIT{print "hello world"}; if(/Start/ .. /Stop/) { print "@F\n"}'

but I've recently decided to ditch awk for perl...

Tim

Re: Yet another awk question...

Muthukumar_5 — Sat, 16 Oct 2004 12:34:44 GMT

We can get your required output as,

# awk '/Start/{x=1;y=0}/Stop/{if (y>3){l[y]="\n"; if ($l[1]="id") { print "This report was run on Sat. May 1, 2005" }
> while(i++This report was run on Sat. May 1, 2005
id fname lname
-- ----- -----
1 John Wayne
2 Bill Smith

This report was run on Sat. May 1, 2005
id fname lname
-- ----- -----
1 Mark Williams

HTH.